Acoustic coupler for earphones



Feb. 5 1952 J. VOLKMANN ACOUSTIC COUPLER FOR EARPHONES Filed June 5, 1944 Izwenoa @222? VOWWQI, y

Patented Feb. 5, 1952 UNITED ES PAT T O F F IC E, 2,584,402

ACOUSTICCOUPLER FOR EAR'PHONES" John; Volkmann, Cambridge, Mass assignor to.

the United States of America as representedby the Executive Secretary of the Ofice o f Scientific Research and Development Applicationlune 5, 1944, Serial No, 538,845

2 Claims. (Cl. 181 -23) Th s inven ion relates; to. n. acoustic oupler foryea ph nes an .1 nor sp cially toc naco st 1 cpupleifoijthe type whi h is-japtedj fl e l p:

ortedm h 7 u er ear. n a positio suchi hat: t may o er t e ar analpen na; usp oy ding an orificial'sealand excluding ambient noise.

Conventional couplers consisting of an. earphone, socketportion and a short tubular bods have already been proposed; These devices are not readily located andiheldj in a properly sea-lei position relative to the ear canal opening, and

when increased pressure is exerted to force the;

coupler into aproperly sealed relation, discome fort: develops, requiring" that the device he removed after a short period of "use.

It isan object-of the invention; therefore; to

devise-animproved acoustic coupler which may be quickly and accurately locatedin the-outer ear in sealed relation to the ear canal toexclude ambient noise; Another obj ect-isto provide a coupler which may bemaintained in; sealed- 'relation to theear-canal without theuse of-*excessive-; ressure, thereby eliminating discomfort and making;-

it possible to keep the coupler in the ear-ior-prolonged' periods. Itrisiurther anobject of the invention to provide a simple, cheap and more efllcient acoustic coupler;

Theinaturelof the invention and its objects will-:.

be; more fully understood from thefollowing description of the: drawings; and discussion relatingt hereto;

In: theaccompanyingdrawings:

E 81 1118: a view. in; elevation illustrating the endiof thee acousticcouplerof; the inveniara-z a view in elevation of the outer end;

llfig; 4-;isa crosssection takenon; theeline A s-4,;

Fig;- 5"is;across .section taken on the line 5:4"

F -f. 6 is. a,v diagrammatic view illustrating.- in. plan-cross section an ear canal with the coupler of the, invention located in: apposition thereto; nd:

Fig, 7 is a. sideelevational view diagrammatiri callyc indicating the. coupler mountedin the ear.

The: coupler in. general includes a base or hon p efer bly or e a r socket for; an; earp resilient. ma eri l uch ubber p a ic, lik s. The ase extends nw r ly: r r d taperedtubular, body which preset its at itsoinner extremity a curved lip portion adapted to, 0on stitutea means for, sealing anlear canal in an improve v manna,

Referring; more 1 in; detail to the drawings nu meral 2 indicates a base or socket for an; ear

phone. The base consists of an annular body having at its outer side a flat. face 4, against which an; earphone 3v (Figure 6) may; be sup! ported and secured, in some suitable manner as by the tapered head 5 engaged in an undercut opening 6.

Extending, outwardly from the peripheral surface of the base 2 is a projection l which may, for exampl'e be fans-shaped, At its ends'the projection is formedwith lug portions I a and I b, as.

illustrated 'inFigures 1, 2 and 3. The projection I serves as a means of attaching the; coupler to a; wire bracket 9 which passes around the coupler and is in turn secured to a headband ll., fragmentaril illustrated. in Fig, 7, As will be noted rom; a sp ctio o F sh 2. t ebmckfl 5 s e nsuc camanne ha t e sa ainst he er surfa e o the" ection. and. hen. pass s-wh ck o thelusp tions a and This: prevents'rotation of'the coupler with respect, to

to'and merge with the smaller circularshape of' the passageway '1'.

i' The tubular extension Hlterminates in a scale ingelement-consisting: of an irregularly shaped lip: l2 which extends: all the wayaround the tubular portion: Asviewed from the innerside- (Fig. i), it will be seen that thesealinglipconsists' of aroughly oval-shaped body havinga front ed e I 3 and a rear edge I 4; At the ends ofitslonger axisthe oval shaped body. is formed with rounded portions l5, and It at the topand bottom respectively. The oval shape-referred to, and especially the rounded portions l5; and I6,

correspond to a similar shape which generallycharacterizes the cartilage portions immediately surrounding the, entranceto an averageearcanal.

Along the front edge Hi, the sealing lip is; cured oveizupon itself to provide a rolled edgeportion havingan arc of a relatively small radius, Alqll .thei-roundedportions l5 arid-l6, the radius of thearc of, curvature of the lip gradually. in creasesand at therear portion Hlthelip flattens out and reaches its greatest .widtln It should; be

observed that, as a result of this arrangement the 3 front edge I3 is arranged in close proximity to the axis of the tubular extension I0, while the rear edge I4 is spaced away from the axis of the tubular extension II) to a much greater extent.

As the lip flattens out along the rear edge I4, it also extends inwardly a greater distance than does the front edge I3 relative to a plane passing through the fiat face 4 of the base, and as a result the lip assumes a somewhat offset position with respect to the tubular member.

In general, the coupling provides an improved seal by means of the compliant lip shaped to conform to an ear canal opening and to fill in around the surrounding cartilage portions. The lip, due to its rolled edge construction, develops axial resilience so that it may be firmly held in place with pressure being uniformly distributed.

In Fig. 6 of the drawings, I have illustrated, in plan cross section, an ear I I and an ear canal I8, with the acoustic coupler of the invention being indicated in an operative position relative thereto.

It will be seen that the sharply curved edge I3 is adapted to engage in back of the tragus I9 (Figure 6), conforming to the sharply curved character of this portion of the tragus. The rear edge I of the lip contacts the cartilage portion 20, with the flattened lip portion spreading out over the cartilage portion 20. As is diagrammatically indicated in Fig. 6, the rounded portions I and I6, as already noted, fill in around the top and bottom of the ear canal orifice. By this arrangement all portions of the ear surrounding the ear canal opening are completely contacted by the lip and an effective oriflcial seal is obtained which efficiently excludes sound.

At the same time, the arrangement of the sharply curved front edge I3 in close proximity to the axis of the communication channel 8, permits a substantial part of the communication channel opening 8 to lie directly in apposition to the ear canal I8. The oval shape of channel 8 particularly corresponds to a somewhat similar oval shape found at the orifice of the ear canal, and thisfurther serves to provide for a relatively large portion of the communication channel 8 occurring in apposition to the ear canal opening.

As will be observed in Fig. 6, the tragus I9 extends part way across the opening of the ear canal I8. As a result it is sometimes difficult to obtain a seal against the inner side of this part of the ear. The off-set arrangement of the lip portion, relative to the tubular extension In, is particularly suited to overcoming this difficulty. The sharply curved forward edge I3 of the lip, by reason of its angular disposition, tends to fall into a position in back of and against the inside of the tragus I9, while the opposite edge I4 of the lip comes into contact with the cartilage portion 20 (Fig. 6) of the outer ear, and is slightly distorted and bent back to conform to the shape of the cartilage portion 20.

The inclination of the lip portion also tends to cause the coupler naturally to assume a position in which an effective seal is obtained, and no difficulty is experienced in quickly and properly locating the lip member in the ear. No excessive pressure is required in order to fit the coupler against the ear portionssurroundin g the ear canal in an effort to secure a seal, as a light pressure quickly engages the offset lip in a position in which it contacts all portions of the ear with uniform pressure, and with a complete sealing action.

The extended or flattened rear edge is especially advantageous from the point of view of maintaining the coupler in the ear for prolonged periods. Such pressure as is exerted to hold or support the coupler against the ear is distributed by this flattened rear edge over a, much greater area of the sensitive cartilage portions and no localized pressure area is developed, with consequent discomfort.

The fan-shaped projection and lugs constitute a simple and efficient means of securing the coupler to a head band and is especially desirable from the point of view of positively resisting rotation so that a permanent location of the lip member in relation to the ear canal may be maintained.

It should be observed that there occurs appreciable variation in the size and shape of ear canals of different individuals. An average ear canal, and its immediately surrounding cartilage portions,"arecharacterized by an oval shape. The oval shape of the lip of the invention is, there-. fore, particularly adapted to fit an average ear. The thin irregular lip construction and its oval shape effectively meet most variations which are to be encountered.

The combined effect of a design which is fitted to the shape of the ear canal opening so that a minimum of pressure is required to obtain a seal, and the use of a flattened rear edge for distributing such pressure as is required, is to eliminate discomfort almost entirely, and to pro duce a coupler which may beu sed without interruption over long periods. A practical result of this is that telephonic communication can be maintained continuously and dependably between given stations over long periods of time.

While I have shown a preferred embodiment of my invention, it should be understood that various changes and modifications may-be resorted to, in keeping with the spirit of the invention as defined by the appended claims.

I claim:

1. An acoustic coupler for earphones'comprising a base member having a sound communication channel formed therein, a tubular extension on said base member, sealing means for sealing the opening of an ear canal from sounds other than those emanatin from said communication channel, said sealing means being located at the end of said tubular extension to be placed nearest the ear canal, said sealing means comprising an irregularly oval-shaped body of fiexible material having a front edge portion at one end of the shorter axis of said oval-shaped body, said front edge'of said body having a rolled edge portion curved over upon itself in the direction of said base member forming an arc of relatively small radius adapted to fit within the tragus of an ear, top and bottom edge portions extending from said first edge portion increasing in width rearwardly, a flattened rear edge portion merging into said top and bot-' tom portions whereby said top, bottom and rear portions are adapted to conform to the cartilage sections of an ear, a laterally offset opening in said body lying along the axis of said extension, means positioning said opening in offset relation to a line perpendicular to the axis of said tubular extension, and means positioning said front edge.

closerv to said base member than said rear edge so that sound carried through said extension will enter the canal of the ear.

2. The combination of claim 1 characterize further by an outwardly extending fan-shaped 2,584,402 5 6 projection on said base member including two REFERENCES CITED lug portfllons: a band and meafns for fixedly The following references are of record in the connecting the said coupler to send head. band me of this patent: including a wire bracket connected to said head band and passing about the coupler and bent to 5 UNITED STATES PATENTS engage against the outer surface of said fan- Number Name Date shaped projection and pass behind said lug por 1,6 12,776 Jone Sept. 20, 1927 tions. 1,753,817 Aber Apr. 8, 1930 2,363,175 Grossman Nov. 21, 1944 JOHN VOLKMANN. 10 2,430,229 Kelsey NOV. 4, 1947 

